Interface IRowMapperCommand

This interface contains commands for mapping columns from a source row to a target row. The source and target can be different from each other, and might be tables, queries etc. in external data sources, or fields and properties in .NET CLR types. It is often used as a worker parameter or property, to allow the user to specify which columns to map or copy. The worker then uses e.g. TypeColumnCopier<TFrom, TTo> to generate a high performance copying delegate, or uses TypeRowMapper<TFrom, TTo>, FromTypeRowMapper<TFrom>, or ToTypeRowMapper<TTo> to create mappings and perform the copying etc. itself.

This interface does include the Row() method, also see IColumnMapperCommand which excludes that method.

See Dataflow Column Mapping and Mapping and Copying for more details.

Note: If the mapping commands result in duplicate mappings, an exception will be thrown. Resolve this by either of:

• Specify additional or all name parts in explicit mapping
• Change the column (or schema) names in the from and/or to rows to avoid name clashes
• Restrict auto-mapping to specific column schemas
• Map offending columns explicitly by name (which will exclude them from later auto-mappings)

Inherited Members

IFluentInterface.GetType()

IFluentInterface.GetHashCode()

IFluentInterface.ToString()

IFluentInterface.Equals(Object)

Namespace: actionETL

Assembly: actionETL.dll

Syntax

public interface IRowMapperCommand : IFluentInterface

Methods

AutoName()

Map automatically by name. Identical names will match, as will partial names where one or more of the left-most parts of the name have been left out. E.g., "Person.Name.FirstName" would automatically map to either of "FirstName" and "Name.FirstName". More matching parts take precedence over fewer matching parts.

Column name matching is ordinal case insensitive, but a case sensitive match takes precedence over a case insensitive match.

The mapping only considers readable (see CanRead) 'from' columns and writable (see CanWrite) 'to' columns.

Note: If there are still more than one possible mapping, an exception will be thrown. Resolve this by either of:

• Change the column names in the row(s) to avoid name clashes
• Use one of the overloads that allows restricting the auto-mapping to specific hierarchy names
• Map offending columns individually by name (which will exclude them from later mappings), before calling this auto-mapping method

Declaration

IRowMapperCommand AutoName()

Returns

Type	Description
IRowMapperCommand	The IRowMapperCommand instance itself, which allows chaining commands.

Exceptions

Type	Condition
InvalidOperationException	Duplicate matches. Mapping the row as a single unit is mutually exclusive with commands mapping individual columns.

AutoName(Int32)

Map automatically by name. Identical names will match, as will partial names where one or more of the left-most parts of the name have been left out. E.g., "Person.Name.FirstName" would automatically map to either of "FirstName" and "Name.FirstName". More matching parts take precedence over fewer matching parts.

Column name matching is ordinal case insensitive, but a case sensitive match takes precedence over a case insensitive match.

The mapping only considers readable (see CanRead) 'from' columns and writable (see CanWrite) 'to' columns.

Note: If there are still more than one possible mapping, an exception will be thrown. Resolve this by either of:

• Change the column names in the row(s) to avoid name clashes
• Use one of the overloads that allows restricting the auto-mapping to specific hierarchy names
• Map offending columns individually by name (which will exclude them from later mappings), before calling this auto-mapping method

Declaration

IRowMapperCommand AutoName(int assertNumberOfMatches)

Parameters

Type	Name	Description
Int32	assertNumberOfMatches	Assert number of matches.

Returns

Type	Description
IRowMapperCommand	The IRowMapperCommand instance itself, which allows chaining commands.

Exceptions

Type	Condition
InvalidOperationException	Duplicate matches. Mapping the row as a single unit is mutually exclusive with commands mapping individual columns.

AutoName(Int32, String, String)

Map automatically by name. Identical names will match, as will partial names where one or more of the left-most parts of the name have been left out. E.g., "Person.Name.FirstName" would automatically map to either of "FirstName" and "Name.FirstName". More matching parts take precedence over fewer matching parts.

Column name matching is ordinal case insensitive, but a case sensitive match takes precedence over a case insensitive match.

The mapping only considers readable (see CanRead) 'from' columns and writable (see CanWrite) 'to' columns.

Note: If there are still more than one possible mapping, an exception will be thrown. Resolve this by either of:

• Change the column names in the row(s) to avoid name clashes
• Restrict the auto-mapping to specific hierarchy names
• Map offending columns individually by name (which will exclude them from later mappings), before calling this auto-mapping method

Declaration

IRowMapperCommand AutoName(int assertNumberOfMatches, string fromHierarchyName, string toHierarchyName)

Parameters

Type	Name	Description
Int32	assertNumberOfMatches	Assert number of matches.
String	fromHierarchyName	Hierarchy from name to include, or null to include all members. Name parts can be omitted from the right, e.g. specifying "Person" will only auto-map from the "Person" member residing directly in the root of the row class, and any descendants of "Person".
String	toHierarchyName	Hierarchy to name to include, or null to include all members. Name parts can be omitted from the right, e.g. specifying "Person" will only auto-map to the "Person" member residing directly in the root of the row class, and any descendants of "Person".

Returns

Type	Description
IRowMapperCommand	The IRowMapperCommand instance itself, which allows chaining commands.

Exceptions

Type	Condition
InvalidOperationException	Duplicate matches. Mapping the row as a single unit is mutually exclusive with commands mapping individual columns.

AutoName(String, String)

Map automatically by name. Identical names will match, as will partial names where one or more of the left-most parts of the name have been left out. E.g., "Person.Name.FirstName" would automatically map to either of "FirstName" and "Name.FirstName". More matching parts take precedence over fewer matching parts.

Column name matching is ordinal case insensitive, but a case sensitive match takes precedence over a case insensitive match.

The mapping only considers readable (see CanRead) 'from' columns and writable (see CanWrite) 'to' columns.

Note: If there are still more than one possible mapping, an exception will be thrown. Resolve this by either of:

• Change the column names in the row(s) to avoid name clashes
• Restrict the auto-mapping to specific hierarchy names
• Map offending columns individually by name (which will exclude them from later mappings), before calling this auto-mapping method

Declaration

IRowMapperCommand AutoName(string fromHierarchyName, string toHierarchyName)

Parameters

Type	Name	Description
String	fromHierarchyName	Hierarchy from name to include, or null to include all members. Name parts can be omitted from the right, e.g. specifying "Person" will only auto-map from the "Person" member residing directly in the root of the row class, and any descendants of "Person".
String	toHierarchyName	Hierarchy to name to include, or null to include all members. Name parts can be omitted from the right, e.g. specifying "Person" will only auto-map to the "Person" member residing directly in the root of the row class, and any descendants of "Person".

Returns

Type	Description
IRowMapperCommand	The IRowMapperCommand instance itself, which allows chaining commands.

Exceptions

Type	Condition
InvalidOperationException	Duplicate matches. Mapping the row as a single unit is mutually exclusive with commands mapping individual columns.

Index(Int32, Int32)

Map a 'from' column to a 'to' column based on their index in SchemaNodeList.

Declaration

IRowMapperCommand Index(int fromSchemaNodeListIndex, int toSchemaNodeListIndex)

Parameters

Type	Name	Description
Int32	fromSchemaNodeListIndex	From index.
Int32	toSchemaNodeListIndex	To index.

Returns

Type	Description
IRowMapperCommand	The IRowMapperCommand instance itself, which allows chaining commands.

Exceptions

Type	Condition
ArgumentOutOfRangeException	schemaNodeListIndex was outside [0, number of items).
InvalidOperationException	Column already mapped Duplicate column mappings Mapping the row as a single unit is mutually exclusive with commands mapping individual columns.

Name(String)

Map a 'from' column to a 'to' column based on their names.

Column name matching is ordinal case insensitive, but a case sensitive match takes precedence over a case insensitive match.

Declaration

IRowMapperCommand Name(string schemaNodeName)

Parameters

Type	Name	Description
String	schemaNodeName	Name of both the 'from' and 'to' columns. Column schema names can optionally be omitted from the left, as long as the specified name is unique among all columns in the row. E.g., assuming "FirstName" is unique, the following can all identify the same column: "Person.Name.FirstName" "Name.FirstName" "FirstName"

Returns

Type	Description
IRowMapperCommand	The IRowMapperCommand instance itself, which allows chaining commands.

Exceptions

Type	Condition
InvalidOperationException	Member not found Found more than one member match in type Name already mapped Mapping the row as a single unit is mutually exclusive with commands mapping individual columns.
ArgumentNullException	schemaNodeName

Name(String, String)

Map a 'from' column to a 'to' column based on their names.

Column name matching is ordinal case insensitive, but a case sensitive match takes precedence over a case insensitive match.

Declaration

IRowMapperCommand Name(string fromSchemaNodeName, string toSchemaNodeName)

Parameters

Type	Name	Description
String	fromSchemaNodeName	Name of the 'from' column. Column schema names can optionally be omitted from the left, as long as the specified name is unique among all columns in the row. E.g., assuming "FirstName" is unique, the following can all identify the same column: "Person.Name.FirstName" "Name.FirstName" "FirstName"
String	toSchemaNodeName	Name of the 'to' column. Column schema names can optionally be omitted from the left, as long as the specified name is unique among all columns in the row. E.g., assuming "FirstName" is unique, the following can all identify the same column: "Person.Name.FirstName" "Name.FirstName" "FirstName"

Returns

Type	Description
IRowMapperCommand	The IRowMapperCommand instance itself, which allows chaining commands.

Exceptions

Type	Condition
InvalidOperationException	Member not found Found more than one member match in type Name already mapped Mapping the row as a single unit is mutually exclusive with commands mapping individual columns.
ArgumentNullException	fromSchemaNodeName toSchemaNodeName

Row()

Map the whole row. Mutually exclusive with commands mapping individual columns. It is up to the caller to decide how to react to a whole row mapping.

Declaration

IRowMapperCommand Row()

Returns

Type	Description
IRowMapperCommand

Exceptions

Type	Condition
InvalidOperationException	Mapping the row as a single unit is mutually exclusive with commands mapping individual columns

See Also

TypeRowMapper<TFrom, TTo>

TypeRowMappings

FromTypeRowMapper<TFrom>

FromTypeRowMappings

ToTypeRowMapper<TTo>

ToTypeRowMappings

IColumnMapperCommand

TypeColumnCopier<TFrom, TTo>